What did Leonardo da Vinci call his early helicopter-like machine?

Leonardo da Vinci called his early helicopter-like machine the aerial screw.

Leonardo sketched the aerial screw around 1489 in his notebooks. The design used a large helical sail made from linen, supported by a reed framework. Leonardo reasoned that turning the screw could make it rise by pushing against the air, much as a screw advances through wood.

The aerial screw was never built and tested by Leonardo, so it was a concept rather than a working helicopter. Modern historians usually describe it as an important early idea in vertical flight, not as the direct invention of the modern helicopter. Its design also depended on human muscle power that would not have been sufficient to lift the proposed structure.

The name can cause confusion because later writers sometimes call it Leonardo’s helicopter. “Aerial screw” is the more historically specific name associated with the surviving drawing and its helical lifting principle.